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For example, an ancestral species has the alleles a and b fixed in its population, resulting in all individuals having the aabb genotype. When two descendant populations are separated from each other and each undergo several mutations the allele A can occur in one population while the allele B occurs in the second population.
Introgressive hybridization, also known as introgression, is the flow of genetic material between divergent lineages via repeated backcrossing. In plants, this backcrossing occurs when an F 1 {\displaystyle F_{1}} generation hybrid breeds with one or both of its parental species.
Hybrid incompatibility occurs when the offspring of two closely related species are not viable or suffer from infertility. Charles Darwin posited that hybrid incompatibility is not a product of natural selection, stating that the phenomenon is an outcome of the hybridizing species diverging, rather than something that is directly acted upon by selective pressures. [4]
In plants, hybridization mostly generates speciation events, [5] and commonly produces polyploid species. Factors like polyploidy events also plays significant factors for understanding the hybridization events (Example: an F1 hybrid of Jatropha curcas x Ricinus communis ), [ 6 ] because these polyploids tend to have an advantage for the early ...
Alternatives to hybridization include open pollination and clonal propagation. [ 2 ] An important factor is the heterosis that results from the genetic differences between the parents, which can produce higher yield and faster growth rate.
Hybridization without change in chromosome number is called homoploid hybrid speciation. [1] This is the situation found in most animal hybrids. For a hybrid to be viable, the chromosomes of the two organisms will have to be very similar, i.e., the parent species must be closely related, or else the difference in chromosome arrangement will ...
Hybrid vigor is expressed during the plant's early vegetative and reproductive growth stages. Young hybrid seedlings have faster root and leaf development and better canopy development; the mature plant has increased total dry matter, larger panicles (the terminal shoots that produce grain), more spikelets (units of flower) per unit area, increased total weight of grains, and, consequently ...
A simplification of an allopatric speciation experiment where two lines of fruit flies are raised on maltose and starch media. Laboratory experiments of speciation have been conducted for all four modes of speciation: allopatric, peripatric, parapatric, and sympatric; and various other processes involving speciation: hybridization, reinforcement, founder effects, among others.